Polyurethane anti-icing composite coating material and preparation method thereof

Abstract

The invention relates to a preparation method of a polyurethane anti-icing composite coating material, which comprises the following steps: mixing and stirring natural grease and an isocyanate-terminated polyether prepolymer at room temperature to fully disperse the natural grease, and defoaming under vacuum to obtain a defoamed mixture; then, adding a curing agent containing an active hydrogen functional group into the defoamed mixture, mixing and stirring until the mixture is uniformly mixed, and pouring the mixture into a mold; and finally, after standing at room temperature, carrying out heat treatment and curing to regulate and control the lubrication release rate and the cycle stability, thereby obtaining the polyurethane anti-icing composite coating material. The anti-icing composite coating prepared by the invention has a double-phase structure, can realize a lubrication release effect at low temperature, and can maintain low ice adhesion strength in multiple freezing and thawing cycles. The method is suitable for surface anti-icing treatment of cold region equipment, wind power blades, aerospace structures and the like.

Description

Technical Field

[0001] This invention relates to the field of functional polymer composite materials technology. Background Technology

[0002] Low-temperature icing is a common challenge in cold-region engineering and extreme climate conditions, leading to operational disruptions of energy equipment, power facility failures, and increased risks to aviation. Therefore, developing surface coating materials with anti-icing and anti-icing properties has been a key focus in materials science and engineering.

[0003] Existing anti-icing coatings primarily employ three design approaches: First, based on low surface energy materials such as fluorine and silicon, they reduce ice adhesion by regulating interfacial wettability; second, by constructing superhydrophobic micro / nano structures, they reduce the contact area between water droplets and the substrate through a cushioning effect; and third, they utilize hydrophilic polymer networks to form a stable hydrowetting layer at the interface, hindering strong bonding between ice crystals and the substrate. While these strategies typically achieve low ice adhesion strength in initial experiments, they generally face insufficient durability issues in practical applications, primarily including: Low surface energy coatings exhibit rapid performance degradation after environmental wear or contamination, and their superhydrophobic structures are easily damaged by mechanical forces. Hydrowetting coatings, on the other hand, suffer from lubrication failure after freezing. To extend coating life, some studies have attempted to introduce a "lubricant release" mechanism, such as incorporating an oil phase into an elastomer matrix. This allows the oil phase to migrate gradually, forming a liquid lubricant layer at the interface and reducing ice adhesion. While these "oil-in-polymer" coatings show significant initial effects, they also suffer from drawbacks such as the difficulty in precisely controlling the oil phase migration rate, leading to rapid lubrication release in the short term followed by later failure. Furthermore, oils are prone to phase separation or macroscopic defects during freeze-thaw cycles, resulting in decreased coating structural stability and insufficient durability.

[0004] Therefore, how to achieve a stable dispersion of the lubricating phase in the material and maintain low ice adhesion and interfacial stability during long-term freeze-thaw cycles remains a key technical bottleneck in the current field of anti-icing coatings. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polyurethane anti-icing composite coating material and its preparation method. The coating material uses a polyurethane two-component system as the matrix, selects natural oils as the lubricating migration phase, and achieves controllable dispersion and thickness adjustment of the oil phase in the coating by controlling the ratio of isocyanate to active hydrogen functional groups and adjusting the ratio of natural oils, thereby maintaining low ice adhesion strength.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing a polyurethane anti-icing composite coating material, comprising the following steps: Step 1: At room temperature, mix and stir natural oils and isocyanate-terminated polyether prepolymer at a mass ratio of 0.01 to 0.1:1 to fully disperse the natural oils. Then, degas the mixture under a vacuum of -0.08 to -0.05 MPa for at least 10 minutes to obtain the degassed mixture. Step 2: Add the curing agent containing active hydrogen functional groups to the degassed mixture and stir until it is evenly mixed. Then pour it into the mold with a pouring thickness of 0.8-1.2 mm. The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the degassed mixture is 1:1.05 to 1:1.20. Step 3: After standing at room temperature for 10-24 hours, heat to 50±5℃ for 1-2 hours to cure. This is used to regulate the lubrication release rate and cycle stability. After the heat treatment curing is completed, the polyurethane anti-icing composite coating material is obtained.

[0007] The polyurethane matrix refers to the polymer formed by the reaction of the isocyanate-terminated polyether prepolymer and a curing agent containing active hydrogen functional groups.

[0008] Furthermore, the natural oil is one or more of the following: grape seed oil, olive oil, sunflower seed oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

[0009] Furthermore, the mixing speed in step one is 300-600 rpm, and the mixing time is not less than 15 minutes.

[0010] Furthermore, the mixing time in step two is 30-90 seconds.

[0011] Furthermore, the mold described in step two is made of metal or polytetrafluoroethylene (PTFE), and the surface roughness Ra of the mold is ≤ 0.2 μm, which is used to improve the density and adhesion of the coating.

[0012] Furthermore, the mold is a stainless steel or aluminum alloy mold.

[0013] Furthermore, the curing agent is a polyether polyol.

[0014] The present invention also provides a polyurethane anti-icing composite coating material prepared by the method described above. The ice adhesion strength of the polyurethane anti-icing composite coating material is initially 20-30 kPa, and remains below 50 kPa after at least 50 freeze-thaw cycles at -10°C. The contact angle is 65-75°, and the fluctuation range is less than ±5°.

[0015] The beneficial effects of this invention are as follows: This invention provides a polyurethane anti-icing composite coating material and its preparation method. A two-component polyurethane system is used as the matrix, and natural oils are selected as the lubricating migrating phase. The components are mixed in a certain proportion to form the coating. During the material curing process, the natural oils form a uniformly dispersed microphase, which can slowly migrate to the surface at low temperatures to form a dynamic lubricating film, reducing the shear force between ice and the interface and improving de-icing performance. By controlling the oil content and the heat treatment conditions after curing, the lubrication release rate and cycle stability can be controlled.

[0016] The anti-icing composite coating prepared by this invention has a two-phase structure, which can achieve a lubrication release effect at low temperatures and maintain low ice adhesion strength during multiple freeze-thaw cycles. It is suitable for anti-icing treatment of surfaces of cold-region equipment, wind turbine blades, aerospace structures, etc. Attached Figure Description

[0017] Figure 1 A comparison diagram of ice adhesion strength after the initial stage and 50 freeze-thaw cycles for experimental verification 1 and 2 of this invention was prepared. Figure 2 This is a photograph of the polyurethane anti-icing composite coating of the present invention. Detailed Implementation

[0018] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0019] To achieve the above objectives, the present invention provides the following specific embodiments: Example 1: A method for preparing a polyurethane anti-icing composite coating material, comprising the following steps: Step 1: Under room temperature conditions, take natural oil and isocyanate-terminated polyether prepolymer with a mass ratio of 0.01 to 0.1:1 and mix them at a stirring speed of 300-600 rpm for no less than 15 minutes to fully disperse the natural oil. Then, under a vacuum of -0.08 to -0.05 MPa, degas for no less than 10 minutes to obtain a degassed mixture. Natural oils are one or more of the following: grapeseed oil, olive oil, sunflower seed oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

[0020] Step 2: Add the curing agent containing active hydrogen functional groups to the degassed mixture and stir for 30-90 seconds to ensure uniform mixing. After stirring, pour the mixture into the mold with a thickness of 0.8-1.2 mm. The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the degassed mixture is 1:1.05 to 1:1.20. Step 3: After standing at room temperature for 10-24 hours, heat to 50±5℃ for 1-2 hours to cure. This is used to regulate the lubrication release rate and cycle stability. After the heat treatment curing is completed, the polyurethane anti-icing composite coating material is obtained.

[0021] Example 2: Same as Example 1, except that the mold is made of metal or polytetrafluoroethylene (PTFE) and the surface roughness Ra of the mold is ≤ 0.2 μm.

[0022] Example 3: Same as Example 2, except that the mold is a stainless steel or aluminum alloy mold.

[0023] Example 4: Same as Example 1, except that the curing agent is polyether polyol.

[0024] Example 5: Same as Example 1, except that the specific steps are as follows: Step 1: Under room temperature conditions, take natural oil and isocyanate-terminated polyether prepolymer with a mass ratio of 0.01:1 and mix them at a stirring speed of 300 rpm for 25 min to fully disperse the natural oil. Then, under a vacuum of -0.08 MPa, degas for 30 min to obtain the degassed mixture. Natural oils are one or more of the following: sunflower seed oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

[0025] Step 2: Add the curing agent containing active hydrogen functional groups to the degassed mixture and stir. After stirring for 30 seconds, pour it into the mold with a pouring thickness of 0.8 mm. The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the degassed mixture is 1:1.05. Step 3: After standing at room temperature for 10 hours, heat treatment to 50°C for 1 hour is performed to regulate the lubrication release rate and cycle stability. After heat treatment and curing, the anti-icing composite coating material is obtained.

[0026] Example 6: Same as Example 1, except that the specific steps are as follows: Step 1: At room temperature, mix natural oil and isocyanate-terminated polyether prepolymer at a mass ratio of 0.1:1 at a stirring speed of 600 rpm for 60 min to fully disperse the natural oil. Then, degas the mixture under a vacuum of -0.05 MPa for 100 min to obtain the degassed mixture. Natural oils are one or more of the following: grapeseed oil, olive oil, sunflower seed oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

[0027] Step 2: Add the curing agent containing active hydrogen functional groups to the degassed mixture and stir for 90 seconds to ensure uniform mixing. After stirring, pour the mixture into the mold with a thickness of 1.2 mm. The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the degassed mixture is 1:1.20. Step 3: After standing at room temperature for 24 hours, heat treatment is carried out at 55°C for 2 hours to regulate the lubrication release rate and cycle stability. After heat treatment and curing, the anti-icing composite coating material is obtained.

[0028] Example 7: Same as Example 1, except that the specific steps are as follows: Step 1: Under room temperature conditions, natural oil and isocyanate-terminated polyether prepolymer with a mass ratio of 0.08:1 were mixed and stirred at a speed of 500 rpm for 30 min to fully disperse the natural oil. Then, under a vacuum of -0.06 MPa, the mixture was degassed for 40 min to obtain the degassed mixture. Natural oils are one or more of the following: grapeseed oil, olive oil, sunflower seed oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

[0029] Step 2: Add the curing agent containing active hydrogen functional groups to the degassed mixture and stir for 60 seconds to ensure uniform mixing. After stirring, pour the mixture into the mold with a thickness of 1 mm. The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the degassed mixture is 1:1.12. Step 3: After standing at room temperature for 15 hours, heat treatment is carried out at 55°C for 1.5 hours to regulate the lubrication release rate and cycle stability. After heat treatment and curing, polyurethane anti-icing composite coating material is obtained.

[0030] Example 8: The present invention also provides a polyurethane anti-icing composite coating material prepared by the preparation method described in Examples 1-7. The ice adhesion strength of the polyurethane anti-icing composite coating material is initially 20-30 kPa, and after at least 50 freeze-thaw cycles at -10°C, it remains below 50 kPa. The contact angle is 65-75°, and the fluctuation range is less than ±5°.

[0031] like Figure 1 , 2 To further illustrate the technical solution and effects of the present invention, the following preparation experiment verification examples are provided: Preparation Experiment 1: Natural oil and isocyanate-terminated polyether prepolymer with a mass ratio of 0.1:1 were taken and stirred at 25°C for 20 min to ensure that the oil was fully dispersed. Then, the mixture was degassed under a vacuum of -0.08 MPa for 15 min to obtain the degassed mixture.

[0032] A curing agent containing active hydrogen functional groups was added to the degassed mixture, controlling the molar ratio of active hydrogen to isocyanate to be 1:1.1. After stirring for 90 seconds, the mixture was poured into a cleaned, flat mold. The poured sample was left to stand at room temperature for 24 hours to cure naturally. Subsequently, it was placed in an oven at 50±5℃ for 2 hours for heat treatment, and then demolded to obtain the polyurethane anti-icing composite coating material.

[0033] Among them, natural oils can be one or more of sunflower seed oil, sesame oil, and wheat germ oil; or natural oils can be one or more of cottonseed oil, corn oil, grapeseed oil, and olive oil.

[0034] Preparation Experiment 2: Unlike Preparation Experiment 1, no natural oils were added. Isocyanate-terminated polyether prepolymer was taken and stirred at 25°C for 20 min. Subsequently, it was degassed under a vacuum of -0.08 MPa for 15 min to obtain a degassed mixture. A curing agent containing active hydrogen functional groups was added to the degassed mixture, controlling the molar ratio of active hydrogen to isocyanate to be 1:1. After stirring for 90 s, the mixture was poured into a cleaned, flat mold. The poured sample was allowed to stand at room temperature for 24 h for natural curing. Then, it was placed in an oven at 50±5°C for 2 h for heat treatment, and then demolded to obtain a polyurethane control film.

[0035] When testing the ice adhesion strength of the anti-icing composite coating material prepared by the method of this invention, the test sample is fixed on a cold plate, and a cuvette containing 1.5 mL of deionized water is placed on the surface of the test sample, with a contact area A. ice 1cm 2 Then, it was kept at -10°C for 12 hours to ensure complete freezing. Finally, the maximum force (F) required to detach the cuvette from the test film was obtained by pushing the probe of the force sensor vertically towards the cuvette. max ); Here, ice adhesion strength ( τ ice )pass τ ice =F max / A ice Calculation; to ensure reproducibility, the above steps should be repeated at least three times for one sample.

[0036] The ice adhesion strength of the sample prepared in Experiment 1 was 22 kPa, while that of the sample prepared in Experiment 2 was 89 kPa. The ice adhesion strength of Experiment 1 was significantly lower than that of Experiment 2, which did not contain any added natural oils. After 50 freeze-thaw cycles, the ice adhesion strength of the sample prepared in Experiment 1 remained below 50 kPa, while the ice adhesion strength of the sample prepared in Experiment 2 (without added oil) gradually increased to 130 kPa after 50 freeze-thaw cycles.

[0037] like Figure 1 As shown in the figure, experimental tests demonstrate that, under the natural oil addition ratio in Experiment 1, the initial ice adhesion strength of the resulting coating was approximately 30 kPa; after 50 freeze-thaw cycles at -10°C, it remained below 50 kPa, with no obvious delamination, cracking, or performance degradation observed; the coating contact angle remained around 75°, with a fluctuation range of less than ±5°, indicating stable surface wettability and oil distribution. Figure 2 As shown.

[0038] The material described in this invention does not require fluorine-silicone components or surface microstructure design, is easy to form a film, and has green and environmentally friendly components. It is suitable for engineering surface treatment scenarios such as aviation, power, and rail equipment that have high requirements for long-term anti-icing adhesion performance.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a polyurethane anti-icing composite coating material, characterized by, The method comprises the following steps: Step one, under room temperature, mix and stir natural oil and isocyanate-terminated polyether prepolymer with a mass ratio of 0.01-0.1:1 to make the natural oil fully dispersed, then deaerate under a vacuum of-0.08 to-0.05 MPa for no less than 10 min to obtain a deaerated mixture; Step two, add a curing agent containing active hydrogen functional groups to the deaerated mixture and mix and stir until uniform, then pour into a mold with a pouring thickness of 0.8-1.2 mm; The molar ratio of the active hydrogen functional groups in the curing agent to the isocyanate in the deaerated mixture is 1:1.05-1:1.20; Step three, after standing at room temperature for 10-24 h, perform heat treatment and curing at 50±5°C for 1-2 h to regulate the lubrication release rate and cycle stability, and after the heat treatment and curing, the polyurethane anti-icing composite coating material is obtained.

2. The method for preparing a polyurethane anti-icing composite coating material as described in claim 1, characterized in that, The natural oil is one or a combination of grape seed oil, olive oil, sunflower oil, sesame oil, wheat germ oil, safflower seed oil, cottonseed oil, and corn oil.

3. The method for preparing a polyurethane anti-icing composite coating material as described in claim 1, characterized in that, The stirring speed in step one is 300-600 rpm, and the stirring time is no less than 15 min.

4. The method for preparing a polyurethane anti-icing composite coating material as described in claim 1, characterized in that, The stirring time in step two is 30-90 s.

5. The method for preparing a polyurethane anti-icing composite coating material as described in claim 1, characterized in that, The mold in step two is made of metal or polytetrafluoroethylene (PTFE), and the surface roughness Ra of the mold is ≤0.2 μm to improve the compactness and adhesion of the coating.

6. The method for preparing a polyurethane anti-icing composite coating material as described in claim 5, characterized in that, The mold is a stainless steel or aluminum alloy mold.

7. The method for preparing a polyurethane anti-icing composite coating material as described in claim 1, characterized in that, The curing agent is a polyether polyol.

8. A polyurethane anti-icing composite coating material obtained by the production method according to any one of claims 1 to 7, characterized in that, The ice adhesion strength of the polyurethane anti-icing composite coating material is initially 20-30 kPa, and remains below 50 kPa after at least 50 cycles of freezing and thawing at-10°C, the contact angle is 65-75°, and the fluctuation range is less than ±5°.

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